ISTANBUL (Reuters) - Turkish police on Tuesday detained 28 people on allegations of being members of a movement led by U.S.-based Muslim cleric Fethullah Gulen in an operation launched in 28 provinces, state-run Anatolia Agency said.

The group included journalists, lawyers and police officers, and prosecutors have issued arrest warrants for 64 people in the investigation, Anadolu said.

President Tayyip Erdogan accuses Gulen of setting up a 'parallel state' and conspiring to unseat the government with a network of supporters in the judiciary, police and media.

Gulen, whose adherents run schools and are active in the media industry, denies the charges.

The two men were allies until police and prosecutors seen as sympathetic to Gulen opened a corruption probe into Erdogan's inner circle in 2013. Thousands of police officers, prosecutors and judges were sacked or reassigned for alleged links to Gulen.